What It Is and What It Protects Against

The varicella vaccine protects against chickenpox (characterized by fever and itchy rash on the body). There is still a slight chance of developing the chickenpox, even after being vaccinated. The CDC reports that 15 to 20 percent of people who receive one dose of the chickenpox vaccine get the disease, though typically a milder case. One dose of chickenpox vaccine is about 85% effective in preventing chickenpox and two doses offers additional protection. The chickenpox vaccine is nearly 100% in preventing serious cases of chickenpox.

General Use

The chickenpox vaccine is recommended for all healthy children, adolescents, and adults who do not have evidence of immunity or protection to chickenpox. For children, the first dose should be given at 12 months to 15 months; the second is recommended between 4 and 6 years old. Those who previously received one dose of varicella vaccine should receive their second dose for best protection against the disease. It is recommended to avoid use of aspirin products for 6 weeks following the chickenpox vaccination.

Adults over the age of 13 who never received the vaccine or had the chickenpox disease are recommended to get two doses, 28 days apart.

Who Should Not Get It

People who should not receive the chickenpox vaccine include anyone who exhibits the following:

  • severe allergic reaction to gelatin or past doses of the chickenpox vaccine
  • moderate-to-serious illness; it is recommended to wait until recovery before getting vaccinated
  • inability to fight infection due to cancer or cancer treatment
  • immune diseases that lessen the ability to fight infection, such as HIV/AIDS
  • use of steroids or drugs that affect ability to fight infection
  • family history of immunodeficiency
  • recent blood transfusion or blood products (People who recently had a transfusion or were given other blood products should ask their doctor when they may get chickenpox vaccine.)
  • pregnant women are advised to wait until after giving birth; for women who wish to become pregnant, it is recommended to wait one month after receiving the chickenpox vaccine to become pregnant

Potential Side Effects

Though the risk of serious harm from the chickenpox vaccine is small compared with the actual untreated disease itself, the vaccine does hold some risk, from mild to severe side effects. Most people who get the vaccine do not have any problems with it. Serious side effects to the chickenpox vaccine are very rare.

Mild side effects include:

  • soreness or swelling where the shot was given
  • fever
  • mild rash
  • seizure (jerking or staring)
  • pneumonia
  • brain reactions
  • low blood count

Moderate to severe side effects (very rare) include:

  • seizure (jerking or staring)
  • pneumonia
  • brain reactions
  • low blood count